With airline passengers getting increasingly concerned about their carbon footprint, the Dutch airline KLM has turned to oil made from the seeds of the camelina plant. On Monday, a KLM Boeing 747 that was partly fueled by camelina oil flew over the Netherlands in a test flight with about 40 passengers aboard.

Airlines have been searching for alternatives to conventional jet fuel. Last January, Continental used a combination of algae and jatropha, a tropical shrub, on a short flight. And Japan Airlines tested a camelina mixture earlier this year.